This invention relates to a silicic polyimide precursor and a process for producing the same.
Japanese patent publication No. Sho 43-27439/1968 discloses a polyimide prepared from a silicic diamine and a diacid anhydride. However, when such a silicic polyimide is applied to protecting materials, insulating materials, etc. in the electronic field, coatings prepared therefrom and after baking have an insufficient strength, hardness, etc. On the other hand, while polyimides containing silicon in the molecule have been prepared for improving adhesion onto silicon wafer, etc., these polyimides use a silicic diamine having the greater part of the diamine component thereof replaced by an aromatic diamine (U.S. Pat. No. 3,740,305, Japanese patent application laid-open No. Sho 57-143327/1982). Coatings prepared from such polyimides and after baking have a sufficient strength, hardness, etc., but adhesion onto silicon wafer, glass or the like cannot yet be regarded as sufficient.
In view of such a present status, the main object of the present invention is to provide a compound which affords a coating having a conspicuous adhesion onto silicon wafer, glass or the like and also having an improved strength, hardness, etc. after baking, and a process for producing the same. More particularly the object is to provide a silicone-polyimide precursor suitable to use for liquid crystal aligning agent, surface-protecting film, insulating film, etc. for semiconductors; soluble in suitable solvents and when dissolved therein, affording a good workability and also a good coating-firmability; having a superior adhesion onto silicon wafer, glass or the like; and having a superior strength and hardness of coating after baking, and a process for producing the same.